There are a few ways to get yourself to the top of Concepcion. I found the easiest was to leave from the village of Altagracia. It's close you can actually walk to the trailhead in about an hour. Staying at Hotel Central is the obvious choice in town.
The guidebooks highly recommend you take a guide but you can get away with doing it without one if are an experienced hiker. It is incredibly important however to take more then enough water and go with others. There is no shade on the path and the summit reaches 5,280 feet. It will be a long day and you should start before dawn to avoid the intense afternoon heat.
Take care and good luck!